The present invention relates to an electromagnetic pickup cartridge such as a moving-magnet or moving-iron pickup cartridge.
In the reproduction of the 45/45-degree-groove stereophonic disks, the electromagnetic pickup cartridges have been widely used because of their high performance and the ease with which a stylus is replaced. Of the electromagnetic pickup cartridges, the moving-magnet pickup cartridges are especially preferred and the moving-iron pickup cartridges are also used. In order to improve the performance of the electromagnetic pickup cartridges, the improvements of a vibration system consisting of a stylus, a cantilever, an armature and a damper must be made so that the stylus velocity can be faithfully transmitted. At the same time, it is also essential to reduce not only the variations in performance of the pickup cartridges but also the fabrication costs thereof.
The magnets used in the vibration systems of electromagnetic pickup cartridges are very small yet have a high permeability because they are made of rare-earth magnetic materials. In general, the prior art magnets are circular in shape and must be formed with a center aperture, but fabricability of such magnetic materials as described above is poor, so that the fabrication costs are high.